hello ..
iv been testing around to crack a AP with 54e speed and it seems uncrackable !!
i have tested a 4 aps for now , i don't got handshake captured and no arp data received .. any one got the same problem ?

searched alot and got this from aircrack-ng site
with airodump doc :

Now displays “e” following the MB speed value if the network has QoS enabled. See example below: